Model tests under reduced scale can only be used for silo design with free flowing bulk solids. Model tests with cohesive bulk solids are not possible under gravity forces due to the dependency of the bulk solids strength on the consolidation stresses. To perform experiments with silos under reduced scale and using cohesive bulk solids centrifugal forces must be applied. In this paper, experiments under reduced scale using a silo centrifuge are shown. The scale-up from model size to full size scale is possible by calculating the ratio of centrifugal acceleration to gravitational acceleration. An overview of centrifuge studies according silo design is given. The results from experiments with cohesive and fine bulk solids regarding the stress state and the critical outlet dimension are presented in this paper. The critical outlet dimension from silo centrifuge testing is compared with calculated results investigated by the Jenike-method. (c) 2005 Elsevier B.V All rights reserved.